Project Summary/Abstract Detection of beta cell damage or death in blood is an important challenge that could transform basic research, diagnosis and clinical trials in diabetes. We have so far identified dozens of DNA methylation markers unique to ? cells and additional cell types, and developed a method to detect these markers in plasma, resulting in high sensitivity and specificity in the detection of death of ? cells and other cell types. Herein we propose to optimize and validate this sensitive qualitative assay, to allow the simultaneous detection of multiple methylation markers for sensitive identification of cell death in multiple tissues in T1D. Our goal is to determine altered turnover of ? cells, pancreatic exocrine cells and T cells, prior to and during the development of T1D. We hope ultimately to perform a methylome- wide analysis of T1D plasma. Such data will facilitate a better understanding of cell death in T1D, and enable the development of markers to assess interventional strategies. We will apply these techniques using both archived material and freshly isolated blood from patients and healthy volunteers. The project is a collaboration between Desmond Schatz (University of Florida), Yuval Dor (Hebrew University) and Carla Greenbaum (Benaroya Research Institute). The investigators have a long history of joint efforts in T1D and are actively involved in TrialNet, ITN, TEDDY, nPOD and T1D Exchange, networks that will all contribute to these studies.